Three-dimensional printing, also known as additive manufacturing, is a process of making a three-dimensional solid object from a digital model of virtually any shape. Many three-dimensional printing technologies use an additive process in which an additive manufacturing device forms successive layers of the part on top of previously deposited layers. Some of these technologies use extrusion printing in which an extruder emits a melted build material, such as heated and softened ABS plastic, in a predetermined pattern. The printer typically operates the extruder to form successive layers of the build material that form a three-dimensional printed object with a variety of shapes and structures. While many printers employ an extruder that includes a single nozzle to emit the melted material, some extruders include multiple nozzles.
One challenge that confronts the operation of three-dimensional object printers includes the proper alignment of the extruders with an underlying surface that receives the melted material to form the three-dimensional printed objects. In many printers, the extruder emits a first layer of the melted build material onto a flat receiving member and forms each successive layer of build material over an external layer of the partially completed three-dimensional object. During operation, if the extruder deviates from a parallel orientation with the underlying receiving member, the face of the extruder may distort the shape of the melted material, which may reduce the quality of three-dimensional printed objects. Multi-nozzle extruders that include larger extruder faces with arrays of nozzles are especially susceptible to angular deviations from parallel with the underlying receiving member. The distortions of the build material compound over multiple layers of a three-dimensional object and may reduce the quality of three-dimensional printed objects that the three-dimensional object printer forms using the improperly aligned extruder. Consequently, improvements to three-dimensional object printers that enable measurement and correction of angular deviations in multi-nozzle extruders would be beneficial.